Abstract
We have investigated the Se isotope effect in the layered bismuth chalcogenide (-based) superconductor with and . For all examined samples, the Se concentration, which is linked to the superconducting properties, is successfully controlled within in . From the magnetization and electrical resistivity measurements, changes in are not observed for the samples with and isotopes. Our result may indicate that the pairing in is not mediated by phonons, which is consistent with recent theoretical and experimental studies suggesting unconventional superconductivity in the -based superconductors.
- Received 9 January 2018
DOI:https://doi.org/10.1103/PhysRevB.97.094509
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